Prevalence and first genetic identification of Cryptosporidium spp. in cattle in central Viet Nam

We investigated the prevalence of Cryptosporidium infection in relation to age and clinical status in cattle in the central region of Viet Nam. A total of 266 fecal samples from diarrheic and non-diarrheic cattle were examined by the modified Ziehl-Neelsen staining method. Prevalence of Cryptosporidium parvum type infections, those of the Cryptosporidium andersoni type, and mixed infection of both types was 33.5% (89/266), 5.6% (15/266), and 3.4% (9/266), respectively. The infection rate of 44.3% (35/79) of C. parvum in calves less than 6 months old was significantly higher than that of 28.9% (54/187) in cattle greater than 6 months old (P < 0.01). Although no C. andersoni oocysts were detected in calves less than 3 months old, no significant difference was observed between the age groups in the prevalence of C. andersoni infection and mixed infection. The percentage of diarrheic and non-diarrheic cattle identified to be shedding C. parvum oocysts was 46.5% (74/159) and 14.0% (15/107), respectively (P < 0.0001). The risk of diarrhea was 1.7 times greater in C. parvum-infected calves than in their non-infected counterparts. DNA sequences of 18S rRNA genes of C. parvum type and C. andersoni type indicated that they were C. parvum bovine genotype and C. andersoni, respectively. This is the first genetic identification of C. parvum bovine genotype and C. andersoni from cattle in Viet Nam.     

Effect of Vermicompost in Media on Growth,Yield and Fruit Quality of Cherry Tomato (Lycopersicon esculentun Mill.) Under Net House Conditions

Effects of VC application on tomato production and media properties can last for the third successive season, which was verified in this study to evaluate effects of VC application on growth, productivity and fruit quality of cherry tomato for the third season. Six treatments were designed similarly in the first and second seasons (unchanged design compared to the previous season), including: VC with rice husk ash (RHS) and coconut fiber (CF) 0% VC+ 50% RHS +50% CF (T1- control), respectively. 20%VC + 40% RHS + 40% CF(T2), 40% VC+ 30% RHS + 30% CF(T3), 60% VC + 20% RHS + 20% CF(T4), 80% VC + 10% RHS + 10% CF(T5), and 100% VC(T6). The results showed that the pH, EC, N, P, K, Ca, and Mg available in media were increased with the addition of VC. This finding revealed that the addition of VC significantly improved the physic-chemical media properties, increasing the EC and also increasing the macronutrients in the media resulting in substantial increased the yield and quality of tomato fruits. It is concluded that EC of VC was the key factor for the positive increase of the productivity and quality of tomato and the salinity (EC at 3.52 dS/m) causing restriction of water to fruits that resulted in the increase of the total soluble solids in tomato fruit and without affecting yield reduction.     

Germplasm Management of Faba Bean (Vicia faba L.): Monitoring Intercrossing between Accessions with Inter-plot Barriers

Knowledge of gene flow is essential for designing strategies of germplasm multiplication. Inter and intra-plot gene flow and pollen dispersion between small plots in a field of Vicia faba germplasm multiplication were measured under four isolation zones at two locations. The four isolation zones were: a barren zone, a nucleocytoplasmic Vicia faba male sterile line, a Vicia faba tetraploid genotype and a Vicia narbonensis L. population. Genotypes fixed for alternative isozyme and allozyme alleles allowed the identification of inter and intra-plot hybrids through progeny testing. A set of log-likelihood ratio (LLR) G tests were used to analyze the effects of geographical location, isolation zone and genotype on the different components of gene flow. Considerable heterogeneity among the genotypes in all the components, inter and intra-plot gene flow and pollen dispersion, of gene flow has been found. It has been shown that gene flow is location, isolation zone and genotype dependent. Planting a barrier surrounding the plots rather than using a non cultivated area between plots seemed more or less efficient for preventing inter-plot gene flow depending on the genotype and the location. Specific associations between genotype and male sterile or tetraploid border rows for every location can bring about gene flow as high, or even higher, than those produced by a barren zone. Differences among the genotypes and borders in flowering overlapping appear not to be the major factor influencing the pattern of gene flow. Implications of the pattern of gene flow observed are discussed in relation to crop diversity managed by farmers.     

Practice on improving fattening local cattle production in Vietnam by increasing crude protein level in concentrate and concentrate level

Two experiments were conducted to determine the effects of crude protein (CP) level in concentrate (experiment 1) and concentrate level (experiment 2) on feed intake, nutrient digestibility, nitrogen (N) retention, ruminal pH and NH₃-N concentration and average daily gain (ADG) of Vietnamese local fattening cattle. Animals (24 cattle, initial live weight (LW) 150.3?±?11.8 kg in experiment 1 and 145.1?±?9.8 kg in experiment 2) were allotted based on LW to one of four treatments in a randomised complete block design. In experiment 1, concentrate with four levels of CP (10, 13, 16 and 19 %) was fed at 1.5 % of LW. In experiment 2, concentrate was fed at 1.0, 1.4, 1.8 and 2.2 % of LW. In both experiments, roughage was 5 kg/day native grass and ad libitum rice straw (fresh basis). Results showed that the CP level in concentrate significantly affected dry matter (DM) intake (P?<?0.05), N retention, ADG and ruminal NH₃-N concentration (P?<?0.01), but it had no significant effect on DM, organic matter (OM) and neutral detergent fibre (NDF) digestibility (P?>?0.05), whereas CP digestibility increased (P?<?0.001) along with the CP level. DM intake, N retention and ADG increased (P?<?0.001) linearly with concentrate intake. DM and CP digestibility were not significantly affected by concentrate intake (P?>?0.05). OM digestibility and NH₃-N concentration increased linearly (P?<?0.05), whereas NDF digestibility and ruminal pH declined linearly with increased concentrate consumption (P?<?0.01). These results indicate that 16 % CP in concentrate and feeding concentrate at the rate of 2.2 % of LW are recommendable for fattening local cattle in Vietnam.     

Timber Demand and Supply in Northwest Vietnam: The Roles of Natural Forests and Planted Trees

Households and wood processing businesses in the provinces of Son La, Dien Bien and Lai Chau in the Northwest of Vietnam were surveyed to determine patterns of local wood demand and supply, changes in species utilized over time, and whether timber from planted trees might substitute for species previously harvested from local natural forests. In each province, 5–6 sawmills and 4–6 villages representing 3 main ethnic groups were selected for investigation. Managers of selected sawmills and 3–4 randomly selected households in each village were interviewed using semi-structured questionnaires. There was high and uniform household demand for fuelwood in the surveyed villages, making fuelwood the dominant use, in terms of wood volume. Use of sawn timber for furniture, home repair and construction consumed less wood but required logs of acceptable species. Sawmills surveyed were small, with input capacity ranging from <15 to 500 m³ of logs per year, suggesting a total log requirement of about 30,000 m³/year for the 192 known wood processing businesses in the three provinces. Most sawmills still used wood from natural forests, sourced locally or imported from Laos. A trend of switching from prized timber species from natural forests, now effectively unavailable, to alternatives from natural and planted forests was reported by both sawmills and households. Some planted species grown on short-medium rotations appear able to substitute for local sawn timber requirements.     

Diffusion of chemicals into archaeological waterlogged hardwoods obtained from the Thang Long Imperial Citadel site,Vietnam

This study shows a method to easily develop suitable impregnation procedure of chemicals for preserving the archaeological waterlogged wood (WW) using diffusion constant. The steady-state diffusion coefficients of polyethylene glycol 4000 (PEG4000), trehalose, and keratin through eight archaeological waterlogged wood species were obtained from the total amounts of the chemicals diffused through the wood samples. The diffusion coefficients were strongly affected by the anatomical structures of the wood species and degree of wood deterioration. Within the same species of wood, the highest diffusion rates were measured in the longitudinal direction, followed by those in the radial and tangential directions. The longitudinal diffusion coefficients were 1.5- to 8.1-times higher than the radial diffusion coefficients, which were in turn approximately 1.1- to 5.7-times higher than the tangential diffusion coefficients. The diffusion rates were found to be inversely proportional to the molecular weight of the diffusing chemical. The diffusivity of trehalose through the waterlogged woods was found to be higher than those of keratin and PEG4000. This study provides a potential method to easily estimate chemical diffusion coefficients for dip-diffusion treatments.     

Determinants of illegal logging in Indonesia: An empirical analysis for the period 1996–2010

Illegal logging is a significant problem in Indonesia, which is one of the few countries with a large forest area. In this study, we investigate the factors that affect harvesting and supply of illegal timber from Indonesia to China and Japan. Moreover, we investigate the factors that lead to the demand of Indonesian illegal timber from China and Japan. A simultaneous-equation econometric model of illegally logged timber demand and supply is developed and tested using the annual data over the period 1996–2010. We find that corruption and decentralization in Indonesia have significant and positive impacts on the illegally logged timber supply while excess demand in Japanese construction and furniture industries as well as Japan’s housing starts are the significant factors that affect the illegal logging in Indonesia. The law enforcement or policies aimed at reducing illegal harvesting in Indonesia are found to be more effective than the policies targeting the import of illegally logged timber into Japan and China.     

Reduced fertility in triploids of <Emphasis Type="Italic">Acacia auriculiformis</Emphasis> and its hybrid with <Emphasis Type="Italic">A. mangium</Emphasis>

Polyploid breeding offers the possibility of increased variability in the search for improved growth, site adaptation and disease resistance in tropical acacias. A key focus of breeding in Vietnam has been the production and testing of vigorous triploid clones which are expected to have the added advantage of being sterile. Triploids obtained by manual crosses between diploid and tetraploid trees or by bulk screening of seedlings derived from open-pollinated seedlots were verified using flow cytometry. Thirteen clones are under field testing for growth rate, tree form and fertility. Six of these are now reproductively mature and flowered as prolifically as diploids. However no pollen germinated, either on agar or on their own stigmas under controlled pollination. Only one clone (X01—F₁ hybrid of tetraploid A. mangium and diploid A. auriculiformis) produced open pollinated pods on 0.05% of hermaphrodite flowers and these contained an average of 1.3 filled seeds per pod, about one-fifth the number observed in diploids. Less than 25% of germinated progeny from this triploid clone survived at 3 months after sowing and survivors were severely stunted with arrested growth. Ploidy and genotype analysis revealed them to be predominantly aneuploids, ranging from hyperdiploid to hypotetraploid with 95% being selfs. We are confident that we can select triploid clones which will be effectively infertile if deployed in plantations and may be of particular value in situations where the normal prolific natural regeneration of tropical acacias is highly undesirable.